Huge Quality Score Drop For Google AdWords Advertisers

I am seeing widespread reports of Google AdWords advertisers complaining that their AdWords Quality Score has dropped significantly across their accounts and ads.

There are two different threads (and soon to be many more) at the AdWordsHelp forums with complaints and posts on Twitter and I have several emails about this.

The quality score drop these advertisers are noticing are in the range of about 3 to 4 numbers, which is massive and incredibly scary for advertisers. The lower the quality the score the less likely your ads show and the more likely you have to pay more for the ads.

Here are some quotes from the threads:

I saw a huge drop in our overall quality score (measured by a script and spreadsheet) for yesterday, from almost 7 in average to 5 down in average.

I can confirm I have the same issue. I use labels to keep track of QS in the interface level and the keywords labeled 9/10 now have a 6/10 , and all keywords lost 2-3 QS points. I updated the keyword labels just yesterday so the change occured this morning.
QS8 are now QS6 , QS7 are QS4. I hope it is a temporary technical glitch.

My keywords quality score was suddenly reduce from high to low. What may be the reasons can anyone please explain me the issues regarding this? And i utilize all my keywords in both landing page and adcopy

One advertiser said he spoke to a representative at Google and they confirmed it was a bug, but we have yet to hear that from Google yet.

Just spoken to someone at Google and this is a widespread issue/bug that has affected many accounts in the UK. Their engineers are looking into it but they couldn't give a timeframe when it will be fixed.

Update: A Google spokesperson told us this is a reporting bug and does not impact ad rank:

We're aware of a bug that is affecting quality score reporting and are actively working to fix this. Rest assured, the bug affects reporting only, not ad serving. We're currently rolling out fixes and expect all accounts to see normal reporting by tomorrow.